The field of the disclosure relates generally to electric machines, and more specifically, to methods and apparatus for mounting a motor controller on a stator assembly.
As described herein, at least one existing motor control assembly is situated in an aluminum housing which is subsequently attached to a motor chassis, adjacent an end shield. In another described motor, a “mid-shield” is installed into the motor chassis, which supports the motor bearing, and allows for the components of the motor control assembly to extend into the motor chassis, eliminating one end shield from such motor assemblies.
Solid end shields obstruct airflow. As a consequence of using a solid end shield, electronics in the motor control assembly do not get adequately cooled. In addition, the windings of the motor are not adequately cooled when an end shield is incorporated between the windings and the motor controller. Reliability and efficiency of the motor may suffer.
Other attempts at mounting a control assembly on stator assemblies have been made. In one process, posts are molded around the perimeter of a plastic stator end-cap and corresponding mating holes are created in the circuit board of the motor control assembly to fit with these posts. After the circuit board is seated, the protruding ends of the posts that extend beyond the board are melted down to hold the board in place. Such a process is slow, prone to human error, and impractical for rework.
In another configuration, snap-in fingers are formed around the plastic stator end-cap. These flexible fingers allow the circuit board of the motor control assembly to snap in and hold it in place. The snap-in fingers are part of the end-cap structure and one drawback to such a configuration is that the protruding fingers tend to interfere with the stator winding process, and the snap-in fingers may break off from handling in the manufacturing process.